Comparison of Antimicrobial Activities of Chitosan and Conventional Root Canal Irrigation Solutions: Systematic Review and Meta-Analysis of in Vitro Studies

Objective: This meta-analysis compared the antibacterial activity of chitosan (Ch) versus conventional root canal irrigating solutions.Methods: A search was performed in three electronic databases (PubMed, Scopus, Web of Science) until June 11, 2025, in two languages (English and Turkish). Studies with missing, unclear, and insufficient data sets were excluded. Two independent reviewers assessed the included studies using the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies. The meta-analysis of standardized mean difference was performed using a random effects model. Additionally, funnel plots as well as Egger's regression intercept test were used to evaluate potential publication bias.Results: A total of 290 samples were used in five included studies. There was no statistically significant difference between the antimicrobial activity of Ch and NaOCl (p=0.536). The mean effect size was -1.368, with a 95% confidence interval (-5.696 to 2.960). There was no statistically significant difference between the antimicrobial activity of Ch and chlorhexidine (CHX) (p = 0.09). Results were SMD: -5.139; 95% CI: −11.085 to 0.807. There was no statistically significant difference between the antimicrobial activity of Ch and the Mixture of Tetracycline isomer, Acid, and Detergent (MTAD) (p = 0.06). Results were SMD: -21.035; 95% CI: −42.664 to 0.595. Eggers' test results showed p-values of 0.65, 0.04, and 0.07, respectively. The funnel plots were also symmetrical.Conclusions: Based on data from the included studies using the well diffusion method, Ch appears to have comparable antimicrobial activity to NaOCl, CHX, and MTAD, suggesting potential as an alternative irrigant.